Most experts agree that the best way to get omega-3 fatty acids is by eating fatty fish, which contain the highest amounts of EPA and DHA. These fish include salmon, mackerel, and trout. “Whole fish provides additional nutrients and bioavailability advantages over supplements,” says Avena.
Research generally supports this recommendation. Most trials examining the health benefits of fish oil supplements have been inconclusive, Dr. Yassine says. “Fish is complex. Even the actual DHA and EPA in fish is not the same as what is present in supplements,” he adds.
For people who don’t eat fish, Avena says algal oil is the best plant-based source of DHA and EPA because it’s derived from the same marine algae that fish consume.
Flaxseed, chia seeds, hemp seeds, and walnuts contain alpha-linolenic acid (ALA), which can be converted into EPA and then to DHA in the body, but not very efficiently, which is why consuming marine food sources is preferable.
How Much Omega-3s Should I Get?
The Dietary Guidelines for Americans, 2025–2030, recommends consuming a variety of protein foods from animal sources, including seafood.
The average size of a fish filet is around 8 ounces (oz) when raw and 6 oz when cooked (use the size of your hand as a guide to portion size), so it’s best to aim for one or more servings a week.
But even if you’re only getting one serving of fish per week, the brain may benefit. “Research shows that when comparing people who are consuming one or more servings of fish per week to those who are eating less, fish eaters experience less cognitive decline over the years,” Dr. Agarwal says.
“That should be encouraging, because this is a simple lifestyle modification to maintain brain health,” Agarwal says.
For those who prefer supplements, Rizzo says most fish oil supplements are 1,000 milligrams (mg). There are no universal recommendations for omega-3 supplements, but the FDA specifies that the labels of dietary supplements should not recommend a daily intake of EPA and DHA higher than 2 grams (g).
At high doses, fish oil supplements may act as a blood thinner, increasing the risk of bleeding in people who take anticoagulant or antiplatelet drugs or any herbs or other supplements that reduce blood clotting.
Always talk to your doctor before adding fish oil or any new supplement to your routine. It’s possible supplements could negatively interact with prescription medications, leading to dangerous side effects.
